REPL Functions

Most of the LFE REPL functions are documented in stdlib reference for their Erlang counterparts. This section documents where the LFE REPL help diverges from the Erlang Shell help.

Compilation

If you view the Erlang reference manual documentation for compiling files in the shell, you will see differences from what is show in the LFE help text. In particular, (c) is for compiling LFE modules and (ec) needs to be used for compiling Erlang source files.

In both cases, the resulting .beam files are compiled to the current working directory and not to an ebin directory. These .beam files will be found by LFE, since the current working directory is included in the path, but you'll likely want to perform some cleanup afterward.

Documentation

You may access the documentation for LFE modules, macros, and functions in the REPL via the doc function. For instance, the Common Lisp compatibility module's documentation:

lfe> (doc cl)
;; ____________________________________________________________
;; cl
;;
;; LFE Common Lisp interface library.
;;
;; ok

That module's cond macro documentation:

lfe> (doc cl:cond)
;; ____________________________________________________________
;; cond
;; args
;; CL compatible cond macro.
;;
;; ok

That module's pairlis/2 function documentation:

lfe> (doc cl:pairlis/2)
;; ____________________________________________________________
;; pairlis/2
;; keys values
;; Make an alist from pairs of keys values.
;;
;; ok

Documentation for Erlang modules and fucntions is available via the Command Interface

Printing Data

LFE Formatting

LFE provides some nice convenience functions for displaying data structions in the REPL. Let's say we had a data structure defined thusly:

lfe> (set data `(#(foo bar baz) #(quux quuz) #(corge grault garply)
lfe> #(plugh xyzzy) #(flurb nirf) #(zobod zirfid)))

We can print our data with the following:

lfe> (p data)
;; (#(foo bar baz) #(quux quuz) #(corge grault garply) #(plugh xyzzy) #(flurb nirf) #(zobod zirfid))
;; ok

Or we can pretty-print it:

lfe> (pp data)
;;(#(foo bar baz)
;; #(quux quuz)
;; #(corge grault garply)
;; #(plugh xyzzy)
;; #(flurb nirf)
;; #(zobod zirfid))
;; ok

Erlang Formatting

The same may be done for displaying data in the Erlang format:

lfe> (ep data)
;; [{foo,bar,baz},{quux,quuz},{corge,grault,garply},{plugh,xyzzy},{flurb,nirf},{zobod,zirfid}]
;; ok

lfe> (epp data)
;; [{foo,bar,baz},
;;  {quux,quuz},
;;  {corge,grault,garply},
;;  {plugh,xyzzy},
;;  {flurb,nirf},
;;  {zobod,zirfid}]
;; ok